Unlike Duch, who was not a member of the ruling clique, Nuon was second in command only to Brother No. 1 Pol Pot, who died in 1998.

Observers say Nuon's case will be more revealing and satisfying for Cambodians who seek to understand better why the Khmer Rouge killed 2 million countrymen in the 1970s, including the brother of Thet Sambath.

Mr. Thet, for one, didn't wait for a court to tell him what he wants to know. Over the past two decades, while the international community negotiated with the government to establish the United Nations-backed tribunal here, Thet was venturing into the jungles of western Cambodia to pose his own questions to Nuon and other Khmer Rouge.

"I want to know what went on inside the Khmer Rouge – why the starvation, why the killing," says the journalist, who teamed up with British coproducer Rob Lemkin for "Enemies of the People." In the film, slated to air on PBS next year, Nuon and other former Khmer Rouge reveal a previously unheard history that contradicts the government narrative.

In the national myth of the liberation, the Khmer Rouge was a monolithic organization that massacred those it imagined to be enemies until regime defectors and their Vietnamese benefactors charged to the rescue. Nuon suggests that the enemies were, to some extent, real. According to Nuon, the Communist Party was engaged in an internal struggle – his group against a powerful pro-Vietnamese faction. Both factions killed enemies, real and perceived.

If Nuon is to be believed, then his court testimony could implicate Khmer Rouge defectors who remain in the highest seats of government today. This may be why the government has been stonewalling the court, say observers. They point to, for example, the refusal of six top politicians to testify despite legally binding orders. Prime Minister Hun Sen, himself a regime defector, has said he'd rather see the court fail than prosecute more people.

Even if this version of history brings the viewer closer to the truth, Thet is careful to point out that none of this absolves Nuon of killing innocents. In the film, Nuon admits publicly, for the first time, that he ordered the killing of thousands of political opponents, which is probably evidence enough to convict him for war crimes – if he ever makes it to trial.